I don't know why but for some unknown reason a command or setup I've done a hundred times with command blocks without fail is now giving me an "invalid command syntax" error message when trying to do or use the "/testfor" command but there is no reason why it should be do that. All my other stuff works fine, it's just for some reason when I try to create a NEW setup I get that error message and I don't know why!

After some last minute testing I've been able to find out that if the command is being issued nearby (same room or area as the player) no error message, but, if the command is imputed farther away with coordinates then it gives the error message. What I don't get though is I have something similar that goes across to the other side of my world and it's fine so why now am I being given this error message? Why is all my other stuff working except for this NEW installation? It also doesn't matter what settings are used on the command block I still get that error message no matter what I do!

I am editing this as I may have just found the cause...!

I believe that it MAY have something to do with the radius (r=...) command as the command was fine when I removed it then when I put it back the error message came back. I need to be able to use that part of the command for a new build in my world... a security feature for my lab actually.